There is described a device for a rotary table provided with means arranged for suspension of a pipe string, the rotary table comprising a rotary ring arranged rotatably about the central axis of the rotary table, the rotary ring more particularly being formed by two or more ring sections, each connected to a system comprising an upper ring support section that in a first embodiment functions as a bearing housing section being rotatable relative to a base section, a bearing housing groove being formed in a base contact surface on the bearing housing section and a corresponding base groove being formed in an opposing bearing contact surface in the base section, said groove having a curve centre coinciding with the central axis of the rotary table, and the rolling diameter of the roller body exceeding the collective depth of said groove, and a channel connecting the end portions of the bearing housing groove being formed in the bearing housing section.
While using a rotary table for suspension and rotation of a pipe string, such as a drill string, where the rotary table typically constitutes the driving element in a drilling machine arranged displaceably in a rig derrick or the like in such a manner that the drilling machine is displaced vertically as the drill string works its way downward in the borehole, there is a need to be able to open the rotary table so that the drilling machine may be pulled away from the pipe string and be displaced vertically to be made ready for another operation. This is particularly relevant in a continuous drilling operation where several drilling machines cooperate in building and rotating the pipe string. In such divisibility it is complicated to provide a sufficiently powerful and functional supporting of the divisible rotary table in a divisible base when the rotary table shall be able to carry a pipe string weight of several hundred tonnes.
From WO 323330 is known a power tong comprising two mutually revolving housing halves, as the housing halves are arranged to be able to be rotated between a closed, active position and an open inactive position, and where a radially split drive ring provided with hydraulically activated clamping jaws directed toward the power tong central axis, is positioned in the housing halves, the drive ring being supported in and connected to a drive motor for rotation of the drive ring about said axis, and the drive ring being provided with at least one locking organ arranged for being able to tie the drive ring parts lockably together.